import React, { Component } from 'react';
import { render } from 'react-dom';
import Button from 'material-ui/Button';

class App extends Component {
    handleClick(e){
        alert('hello.');
    }

    render(){
        return (
            <Button variant="raised" color="primary" onClick={this.handleClick}>
              Hello World
            </Button>
          );
    }

}

render(<App />,document.getElementById('root'));